A Comprehensive In Silico Study of New Metabolites from Heteroxenia fuscescens with SARS-CoV-2 Inhibitory Activity.

Chemical investigation of the total extract of the Egyptian soft coral Heteroxenia fuscescens, led to the isolation of eight compounds, including two new metabolites, sesquiterpene fusceterpene A (1) and a sterol fuscesterol A (4), along with six known compounds. The structures of 1-8 were elucidated via intensive studies of their 1D, 2D-NMR, and HR-MS analyses, as well as a comparison of their spectral data with those mentioned in the literature. Subsequent comprehensive in-silico-based investigations against almost all viral proteins, including those of the new variants, e.g., Omicron, revealed the most probable target for these isolated compounds, which was found to be Mpro. Additionally, the dynamic modes of interaction of the putatively active compounds were highlighted, depending on 50-ns-long MDS. In conclusion, the structural information provided in the current investigation highlights the antiviral potential of H. fuscescens metabolites with 3ß,5α,6ß-trihydroxy steroids with different nuclei against SARS-CoV-2, including newly widespread variants.

Chemical Review of Gorgostane-Type Steroids Isolated from Marine Organisms and Their 13C-NMR Spectroscopic Data Characteristics.

Gorgostane steroids are isolated from marine organisms and consist of 30 carbon atoms with a characteristic cyclopropane moiety. From the pioneering results to the end of 2021, isolation, biosynthesis, and structural elucidation using 13C-NMR will be used. Overall, 75 compounds are categorized into five major groups: gorgost-5-ene, 5,6-epoxygorgostane, 5,6-dihydroxygorgostane, 9,11-secogorgostane, and 23-demethylgorgostane, in addition to miscellaneous gorgostane. The structural diversity, selectivity for marine organisms, and biological effects of gorgostane steroids have generated considerable interest in the field of drug discovery research.

Phytochemical and in silico studies for potential constituents from Centaurium spicatum as candidates against the SARS-CoV-2 main protease and RNA-dependent RNA polymerase.

In the present study, a new secoiridoid glycoside lisianthoside II 1, along with seven known compounds 2-8, were isolated from Centaurium spicatum L. In-silico molecular docking and molecular dynamic simulation against SARS-CoV-2 Main protease (Mpro) and RNA-dependent RNA polymerase (RdRp) were conducted. The affinity docking scores revealed that 8 is the best bound ligand to Mpro active site with binding energy of -14.9877 kcal/mol (RSMD = 1.16 Å), while 6 was the highest against RdRp (-16.9572 kcal/mol, RMSD = 1.01 Å). Moreover, the molecular dynamic simulation revealed that 8 with a (ΔG) of -7.9 kcal/mol (RMSD value of 2.6 Å) and 6 (RMSD value of 1.6 Å) and binding free energy (ΔG) of -7.1 kcal/mol achieved the highest stability over 50 ns of MDS inside the Mpro and RdRp enzyme's active site, respectively. Hence, the isolated compounds could be a good lead for development of new leads targeting COVID-19.

Diadema setosum: isolation of bioactive secondary metabolites with cytotoxic activity toward human cervical cancer.

In our promising project toward discovery of secondary metabolites with potential anticancer activity against human cervical cancer, seven marine organisms were screened for their cytotoxic activity against HeLa cancer cell line using MTT colorimetric assay. The crude extract of the outer shell of Diadema setosum showed promising activity with 88.02% inhibition at a concentration 250 µg/ml. Chromatographic investigation of the Ethyl acetate fraction, which is the main contributor to the activity (IC50= 43.1 ± 5.94 µg/ml), led to isolation of five compounds. Structures of the isolates (1-5) were elucidated by 1 D and 2 D NMR spectroscopy and HR-ESI-MS analysis. 5α,8α-epidioxycholest-6-en-3ß ol (2) and 5α,8α-epidioxycholest-6,9(11)-en-3ß ol (3) showed the highest cytotoxic activity with IC50 values 12.1 ± 2.74 µg/ml and 21.8 ± 6.32 µg/ml, respectively. Epidioxy steroids with cholestane nucleus could be a prospective candidate for the development of drugs for treatment of human cervical cancer.

Ent-trachylobane-3ß-hydroperoxide, a new diterpene from the root bark of Chrozophora oblongifolia (Fam.; Euphorbiaceae).

New ent-trachylobane-3ß-hydroperoxide (5) together with four known compounds, ricinine (1), trimethoxy ellagic acid (2), dimethoxy ellagic acid (3) and aleurotolic acid (4) were isolated from the methylene chloride fraction of the root bark of Chrozophora oblongifolia. The structures of these secondary metabolites were elucidated by using different spectroscopic techniques, 1H NMR, 13C NMR, HSQC, HMBC, 1H-1H COSY, NOESY, HR-ESI-MS, EI-MS and comparison with published data. Ent-trachylobane-3ß-hydroperoxide showed moderate cytotoxic activity by MTT assay method against human breast cancer cells (MCF-7) and human hepatocyte-derived carcinoma cells (Huh-7) with IC50 values of 24.53 and 34.13 µM, in comparison with IC50 values of 23.47 µM and 15.82 µM for 5-fluorouracil respectively.

Two new polyhydroxylated steroids from Egyptian soft coral Heteroxenia fuscescens (Fam.; Xeniidae).

Two new polyhydroxylated steroids, 3ß-acetoxy-gorgost-5α,6ß,11α-triol (3) and (23 R) methylergosta-20-ene-3ß,5α,6ß,17α-tetrol (4), together with three known gorgosteroid compounds, gorgost-3ß, 5α,6ß,11α- tetrol (1), 11α-acetoxy-gorgost- 3ß,5α, 6ß- triol (2), and gorgost-5 (E) ene-3-ß-ol (5), as well as batyl alcohol (6), were isolated from the Egyptian soft coral Heteroxenia fuscescens. The structures of these compounds were elucidated based on NMR spectroscopic analyses, HR-FAB-MS, and comparisons with published data. The cytotoxic activities of the fractions and compounds were evaluated against MCF-7 cancer cell lines using MTT colorimetric assay. Compounds 2 and 4 showed moderate cytotoxic activity, with IC50 values equal to 33.2 and 25.1 µM, respectively, in comparison with the IC50 of 5-fluorouracil 18.7 µM.

Mangostanaxanthone VIII, a new xanthone from Garcinia mangostana and its cytotoxic activity.

A new prenylated xanthone, mangostanaxanthone VIII (7) and six known metabolites: gartanin (1), 1,3,8-trihydroxy-2-(3-methyl-2-butenyl)-4-(3-hydroxy-3-methylbutanoyl)-xanthone (2), rubraxanthone (3), 1,3,6,7-tetrahydroxy-8-prenylxanthone (4), garcinone C (5), and xanthone I (9-hydroxycalabaxanthone) (6) were separated from the EtOAc-soluble fraction of the air-dried pericarps of Garcinia mangostana (Clusiaceae). Their structures have been verified on the basis of spectroscopic data analysis as well as comparison with the literature. The cytotoxic activity of 7 was assessed against MCF7, A549, and HCT116 cell lines using sulforhodamine B (SRB) assay. Compound 7 showed significant cytotoxic potential against MCF7 and A549 cell lines with IC50s 3.01 and 1.96 µM, respectively compared to doxorubicin (0.06 and 0.44 µM, respectively). However, it exhibited moderate activity towards HCT116 cell line.

Forsskamide, a new ceramide from aerial parts of Forsskaolea tenacissima Linn.

Although the various folk medicine uses and the biological activity of Forsskaolea tenacissima L., few chemical constituents of this plant have been reported, this provoked us to make our study. Forsskamide, a new ceramide was isolated from aerial parts of F. tenacissima L. (Urticaceae). The chemical structure was established by different spectroscopic methods (1H, 13C-NMR, HMBC, HSQC, ROESY, FAB-MS and HR-FAB-MS). Forsskamide showed a moderate cytotoxic activity by (MTT) method against human colorectal carcinoma cell line (HCT-116) with IC50 33.25 µM in comparison with 5-fluorouracil IC50 26.42 µM. While, it did not show any activity against human hepatocarcinaoma cell line (HepG-2).

Effect of polyphenols from Vicia faba L on lipase activity and melanogenesis.

Two new flavonoid glycosides, kaempferol 3-O-α-L-rhamnopyranosyl (1→6) (3''-acetyl)-ß-D-galactopyranoside 1 and kaempferol 3-O-α-L-arabinopyranosyl-5-O-α-L-rhamnopyranoside 2, along with six known ones 3-8 were isolated from the flowers of Vicia faba L. (Fabaceae). Methanol extract and the isolated compounds were tested against lipase and melanogenesis inhibition activities and resulted in that compound 2 showed 53 and 77% lipase inhibition activity in concentrations of 400 and 800 µg/mL, respectively. For melanogenesis, compounds 2, 3 and 4 exhibited potent melanogenesis inhibition activity where the melanin content in melanoma cells was decreased to be about 57.5, 56 and 61%, respectively, with no obvious melanocytotoxicity. The rest of compounds showed weak to moderate activity. The results of melanogenesis inhibition activity of this study suggested the potential use of Vicia faba flowers as a skin-whitening agent and reveal the flowers to be a rich source of important phytochemicals with antilipase and melanogenesis inhibitory activity.

Xanthone and lignan glycosides from the aerial parts of Polygonum bellardii all growing in Egypt.

A new long chain fatty alcohol acetate identified as 17-hydroxypentacosanyl acetate, (1) together with a new xanthone identified as 1,8-Dihydroxy-3,6-dimethoxy-xanthone-5-O-[α-L-rhamnopyranosyl-(1''→2')]-ß-D-glucopyranoside (3), as well as two new lignans identified as (+)-Lyoniresinol-3a-O-[α-L-rhamnopyranosyl-(1'''→6'')]-ß-D-glucopyranoside (4) and (+)-Isolariciresinol-3a-O-[α-L-rhamnopyranosyl-(1'''→2'')-α-L-rhamnopyranosyl-(1''''→6'')]-ß-D-glucopyranoside (5), in addition to ß-sitosterol-3-O-acetate (2) were isolated from the methanolic extract of the aerial parts of Polygonum bellardii growing in Egypt. Their structures were elucidated on the basis of different chemical and spectroscopic evidences. The total extract and its fractions, in addition to compounds (3, 4 and 5) showed significant antioxidant potential by DPPH(·) scavenging activity technique.

Two new acetylated flavonoid glycosides from Centaurium spicatum L.

Two new acetylated flavonol glycosides, quercetin 3-O-[(2,4-diacetyl-α-L-rhamnopyranosyl)-(1→6)]-2,4-diacetyl-ß-D-galactopyranoside (1) and quercetin 3-O-[(2,4-diacetyl-α-L-rhamnopyranosyl)-(1→6)]-3,4-diacetyl-ß-D-galactopyranoside (2), in addition to two known acetylated quercetin glycosides quercetin 3-O-[(2,3,4-triacetyl-α-L-rhamnopyranosyl)-(1→6)-ß-D-galactopyranoside (3) and quercetin 3-O-[(2,3,4-triacetyl-α-L-rhamnopyranosyl)-(1→6)-3-acetyl-ß-D-galactopyranoside (4), were isolated from the aerial part of Centaurium spicatum (L.) Fritsch (Gentianaceae). Structure elucidation, especially the localization of the acetyl groups, and complete (1)H and (13)C NMR assignments of these biologically active compounds were carried out using one- and two-dimensional NMR measurements, including (1)H- and (13)C-NMR, DEPT-135, H-H COSY, HMQC and HMBC, in addition to HR-FAB/MS experiments.

New steroidal glycosides from the fruits of Solanum anguivi.

Four new steroidal saponins, anguiviosides III (1), XI (2), XV (3), and XVI (4), were isolated and characterized from the fruits of Solanum anguivi. Their structures were elucidated on the basis of spectroscopic analysis. The occurrence of the cholestane glycosides 3 and 4 is considered from a biogenetic point of view.